Improvement in mills for grinding bones



A. & E; LISTER.

Mill for Grinding Bones.

Patented' Sept. 6, 1870.

@Wina vALFRED LISTER AND EDWIN LISTER, 0F NEWARK, NEW JERSEY.

Letters Patent No. 107,184, dated September 6, 1870. TWL/@' 5170' IIPROVEMENT IN MILLS POR GRINDING- BONES.

The Schedule-referred to in those Letters Patent and making part of the same.

To all whom/it may concern Be it known that we, ALFRED Llsrnu and Enwm LISTER, of Newark, in ,the county of Essex and State of New Jersey, have invented and made a new and useful Improvement in Mills for' Grinding Bones and other articles; and the following is declaredto be a correct description thereof.

Bone is a highly-concentrated fertilizer or restorative of worn-out land, but its production is slow, because no adequate means have before been devised for redneing'the bone to a powder with rapidity and cheapness.

-Boues have lheretofore been cracked and broken up by rollers into lumps of various sizes, and employed as manure. In thisstate the action of the manure is very slow, because the .bones donot decompose with apidity, and the fertiliziug elements are not-easily dissolved.

Efforts have been made to ,reduce the bones to a fine tlour or powder, so that they may becomey soluble, and hence be-absorbed by"vegetation.' These elthrts have not been successful, because the mills heretofore employed are 'liable to become clogged and inoperative, in consequence of the adhesive nature of the boue, particularlywhen warmed by the friction in grinding.

A pair ot' rollers will not pulverize the particles of. bono sufficiently iue, because the bone is very tough and the mass passes through without being suliciently reduced to a powder.

Our invention consists in a grinder, made of a cyl-A inder with cutting-edges upon its periphery, and revolved rapidly, so as to be movingvdownward'at the cutting point, in combination with another cylinder with cutting-edges, and revolved so that its surface at the cutting-point moves upwardly.

By this construction, the surfaces, movingnpward and downward, act as shears to out the bone or other material up into a fine powder, and the cutters do not .become clogged by the bone, because there'is'no jamming r compression of the particles of bone, the 11's-, ing .cutting-surface relieving the particles by lifting them hence there is only a rapid shearing action, that cuts the boue or other material up into very ne particles, with great rapidity, and the centrifugal action keeps the cutting-edges from becoming full of the fine boue or other flour.

In this constrnctiouof mill a hopper is applied .between the two'cylinders, and said hopper can be filled with material to be ground, and the grinding operation will proceed with great rapidity, the cylinders being revolved as aforesaid.

Inthe drawing-.-

Figure 1 is a plan ofthe grinding-mill, without the containing-hopper, and y Figure 2 is a vertical vsection ofthe apparatus, at the line :c x.

The cylinders c and-b are mounted on shafts c and d, and the peripheries of the cylinders are made of plates, with cuttingedges formed by ribs upon the surfaces of saidplates. rI he ribs are atan inclination, so that the cutting-edges act as shears at the grinding-point where the surface-of the cylinder a descends and that of b ascends, as represented by the arrows. l

The plates are secured. upon the heads of fthe cylinders by countersunk bolts, or otherwise, and the 'size of the ribs and the intervening grooves are deeper or Amore shallow, according to the grade of tineness' required in the varticle ground.

` The shaft d is set in adjustable boxes in the frames e e, (see dotted lines in iig. 2,) and the shaft e is also setiu boxes inthe frames e, but these latter boxes are allowed to yield, so as to prevent injury to the cylinders` by any foreign substance that may get in between them, the levers g aud weights, acting upon said boxes, serving vto keep the rollers a b toward each other, but they are not allowed to actually touch, the adjusting-'screws 3 forming steps.

The cylinder a. is propelled rapidly by a. belt to the l pulley h, or otherwise, and the pulley le and gears lm.

may be employed to rotate the cylinder b.

The hopper u is-to set closely uponthe edges of the cylinders, and receives the boues, or small pieces of bones or other material to be ground np into powder of flour, as aforesaid.

Our improvement, although especially intended for grinding bones, may be used for grinding plaster logwood, charcoal, and many other articles, with great rapidity, audwith but'little risk of clogging.

We claim as our inven'tiou-- l The revolving grinding-cylinders e b, the surfaces of which are composed of diagonal cutting-edges, mov-1 ing in opposite directions, substantially in the manner and for the purposes speciti'ed.

Dated this 15th day of J auuary, Ap D. 1870.

y ,ALFRED LISTER. Witnesses: EDWIN LISTER.

JOHN B. RUSSELL, Cass. Glomz. 

